Ok, in no particular order: * Built in BASIC on the Commodore PET * Folders in MS DOS (CP/M didn't have them) * The trashcan in Macintosh System 6 * The sta

Ok, in no particular order: * Built in BASIC on the Commodore PET * Folders in MS DOS (CP/M didn't have them) * The trashcan in Macintosh System 6 * The start bar in OS/2 * I can't think of a single unique thing about Atari TOS * The stability of Windows 2000 (compared to 9x and NT)